Process for concentrating ores.



'B. H. DOSENBACH.

PROCESS FOR CONCENTRATI'NG ORES.

APPLICATION FILED MAR. I, 1918.

' silicates, etc.

BENJAMIN H. DOSENBACH, OF BUTTE, MONTANA.

PROCfiS FOR CONGENTRATING'OBES.

Original application filed December 7, 1915, Serial No. 65,485. Divided and this application filed March i,

To all whom it may concern:

Be it known that I, BENJAMIN H. DosnN- BAorr, a citizen of the United States, residin at Butte, in the county of Silver Bow-an State of Montana, have invented certain new and useful Improvements in Processes for Concentrating Ores, of which the following is a specification.

This application is a division of myocpending application Serial No. 65,485 for a rocess of concentrating ores, filed Decemer 7,1915.

My invention consists in means for concentrating ores by a combination of the leaching and flotation methods, and is particularly directed to' the treatment of copper in which the copper exists in the form of sulfid, together with carbonates, oxids, and 'Hcretofore copper ores, in which the copper occurs in the form of a sulfid, having been concentrated by the flotation method, but ores in which the copper occurs in both the sulfid and forms other than a sulfid cannot be completely con- It has also been found impossible to concentrate orescontaining copper, as oxid, silicate or carbonate, by the ordinary water gravity appliances, such as jigs, tables and vanners, y reason of the fact that the carbonates, silicates and oxids of copper are of comparatively low specific gravity. Attempts have been made to concentrate .ores containing copper, as oxid, silicate or carbonate, by leaching with sulfuric acid. Little success, however, has attended the treatment of copper ores by leaching. If the grinding be coarse, the

copper enters into solution slowly. If'the grinding be-fine, theslimes thereby formed nterfere with the subsequent steps in the operation. After the copper has been dis solved it becomes necessary means for pficipitating the copper and separating it In the sands and slimes. .The' most common methods heretofore applied for this purpose have been the electrolytic deposition of the copper, and the precipitation of the copper by the use of scrap iron. The existence of slimes in the liquor carrying the dissolved copper introduces difiiculties in the application of both of these methods, and no method of leach g copper ores, heretofore devised, has been suficlently eficient to be used to an considerable extent.

to adopt some .55 Furthermore, the leac .'ng proces fis not in troduce airinto the pulp,

1918. Serial No. 220,960.

I have devised my improved process for concentrating copper ores in which occurs as sulfid to ate, silicate, etc.

the copper other with oxid, carbonriefly stated, my process consists, first, in grinding the ore as finely as may be necessary to efi'ect the most rapid and complete solution of the copper, the existence of slimes in the ore pulp being no disadvantage in the application of the subsequent steps of the process. After the sulfuric acid, which is added to the pulp, has dissolved the copper I precipitate the copper, in metallic form, preferably by the use of iron scrap. Up to this point no separation of the copper from the remainder of the ore in thepulp has been effected. The copper in the :oxid form has simply been dissolved, forming the sulfate, and then precipitated as metal, theprccess up to this point consisting simply in transforming the cop er oxids, carbonates, silicates, etc., into meta lie copper, while leaving the sulfid copper unaltered. Having efiectedthis conversion of that the metallic copper and sulfid copper can both be separated by the ordinary flotation methods. At this point, therefore, I ineither by agitation or by passing the air through some porous medium, whereupon the sulfid copper and metallic copper float as floated from the surface of the pulp in the methods ordinarily used in flotation operations. While the air introduced into the pulp by agitation, or by other means, is the principal [instrumentality for separating and floating the copper, it may be that gases, such as hydrogen, carbon dioxid, and hydrocarbons are formed. The generation of hydrocarbon gases I have found to be quite noticeable, resulting probably from more or less complicated actlons taking place between the sulfuric acid, the iron, the carbon and sulfur contained in the iron, the cop.

.a froth and are Specification of Letters Patent. Patented JUUHE Ill, 1913.

is frequently very noticeable.

per minerals contained in the ore, and interactions between the various products formed. Whatever the precise chemical react1ons may be the generation of such hydrocarbon gases floated the copper in the form of a froth and law have obtained a high grade of concentrate and a high recovery without adding any 011 or other frothing agent, whatever, to the pulp, merely sub ectin the pulp to agltation or aeration by ot er means after the copper has been dissolved and precipitated. In other instances I have found it advantageous to add some oil, or other frothing agent, such as turpentine, yroligneous acid, etc, acetic acid, and alcohol. In some instances the formation of a froth is pro moted by the addition of ferrous and aluminum sulfate.

A great many copper ores contain sulfid copper, together with the various oxids, carbonates, silicates, etc., of copper and my process is intended for the treatment of ores of this class- The sulfid copper in such ores remains practically unaltered during the leaching operation by which the oxids, carbonates and silicates of copper are dis solved, and after thedissolved copper is precipitated the application of the flotation step results in floating the sulfid copper, together with the precipitated metallic copper.

It will be obvious that many varieties of mechanism may be employed in the application of my process. As an example of a suitable arrangement of apparatus, I have illustrated in the drawing forming part of this application an arrangement slmilar to that used by me in the application of my process to the Butte ores above referred to.

The drawing is diagrammatic, taking the form of what is generally termed a flow sheet. Detailed illustration and explanation of the apparatus used is unnecessary for the reason that all ofthe apparatus is of a type old and well-known in the art,

Referring to the drawin The ore suitably crushed, say to a maximum size of about one-fourth of an inch, is

' supplied to the apparatus from a bin A. The

sulfuric acid used for leaching may be supplied from a tank lB. The ore and sulfuric acid, together with suficient water to make a pulp of proper consistency, are conducted to a tube mill. C, where the ore is simulsense in which that termhas raoaoto taneously subjected to as fine grinding as necessary, and to the solvent action of the sulfuric acid. Ordinarily the copperoxids, carbonates, and silicates will enter completely into solution in the pulp while in the tube mill referred to, but, of course, 1f a longer interval of time is necessary to effect the solution of the copper than is necessary for the grinding of the ore, the acid may be given further time for acting, by conducting the pulp from the tube mill to some suitable vessel for that purpose. Ordinarily, however, after the ore has been ground in the tube mill in the presence of the added sulfuric acid, the oxid copper will be completely dissolved and the pulp may then be conducted to a horizontal rotating cylinder D, which contains scrap iron, as

indicated at E. I have shown an alternative method of treatment in which the pulp, instead of being conducted directly from the tube mill C, to the rotating cylinder D, is first conducted to a Dorr tank, or other settling device, for subsequent treatment. At present, however, I will describe the method of operation utilized when the pulp is conducted directly from the tube mill C to the rotating cylinder D. In this case the rotatact between the scrap iron therein contained and the ulp which passes through the cylinder D om left to right, as shown in the drawing. The rotation of the cylinder D further has the efl'ect of freeing the surface of the scrap iron from the precipitated copper, and by suitably timing the tion of the cylinder D causes eficient concarries the oxid copper in the form of recipitated or cement copper, as distinguis ed from the carbonates, silicates, and oxids, in a which the copper originally existed. The ob ect of the operation so far described is simply to eflect the conversion of the copper into the metallic form. While the ore has been leached and the copper dissolved in the method employed in leaching processes, the operatlon Is not a leachin process in the heen heretofore employed. The leachin forming part of my process does not, an is not intended to effect directly any separation of the oxidl V copper from the remainder of the ore. The

leaching is simply the first step in the con version of the copper from the silicate, onid, or carbonateform into the form of a free metal, which free metal results from the procipitation of cement to James M. Hyde,

stated, the flotation may .agents,

. acaeao copper by scrap iron in the rotating 0 linder The pulp ischarged from the rotating cylinder D contains the oxid copper in the metallic form together with the unaltered sulfid copper, and in this form the copper originally present as 'oxid is amenable to flotation treatment, together with the unaltered sulfid copper, which treatment may be effected in any of of apparatus, such, for instance, as that illustrated in Patent No. 1,022,085, granted April 2, 1912. As above be eil'ected in apparatus in which the air is introduced into the pulp under sufiicient pressure through a porous wall, or by means of jets. Such means of efl'ecting flotation are illustrated in Patent No. 1,104,735, granted to J. M. Callow July 21, 1914. The flotation operation, however conducted, and whatever apparatus used, results in the flotation of the cement copper, together with the sulfid copper originally contained in the ore and it may be separated in the way ordinarilypractised in flotation-operations. As above stated, I have in some instances found-the addition of a frothin agent, such as an oil, or other ofthe su stances'hereinbefore enumerated, unnecessary, not restricted to the use, or non-use, ofany particular floating agent, and includes the operation regardless of whether the flotation be effected by the addition of frothing or by the properties imparted to the pulp by the various salts formed in the leaching operation.

In the alternative method of procedure above referred to, the pulp, instead of being conducted directly from the tube mill C to the rotary cylinder I), may first be conducted to a Dorr tank, or other settling device F. The clear liquor from the settling device F'is conducted to a scrap iron launder G, where the dissolved copper is precipitated by the scrap iron H, the precipi the well-known forms j in connection with the first unaltered,

but my process is precipitating the copper and the liquor being conducted back to the feed end of the tube mill C. By this means the acid contained "in the clear liquor overflowin from the settling tank F, is saved, thus e ecting some economy in the amount of acid used. When operating according to this method, the thickened material is draw off from the bottom of the settling tank F, and the copper dissolved therein is precipitated by scrap iron in the rotating cylinder D in the manner above described method of operation, after which the precipitated copper and sulfid copper are separated by flotation, as above stated, in connection with the first me hod of operation.

What I claim is:

1. A process of concentrating ores containing copper in different chemical compounds, one of such compounds bein sulfid of copper, which consists in subjectmg the ore to the action of a solvent which causes the non-sulfid copper to go into solution while leaving the sulfid copper substantially precipitating the dissolved copper in the metallic state in the mixture of ore and solvent, and then separating the precipitated copper'and sulfid copper from the gangue by flotation. 2. A process for concentrating ores containing sulfid copper and compounds of copper that are convertible into sulfates by the action of sulfuric acid comprising the operations of subjecting the ore to the action of sulfuric acid thus forming'copper sulfate, in the metallic state in the mixture of ore and acid, and then separating the precipitated copper and the sulfid copper from the gangue by flotation.

In testimony whereof, I have subscribed my name.

BENJN H. nos/anon. 

